Could this weekend's weather be a sign of global warming? Check back, in decades

Apr 27, 2012

Yet another weekend that beats the work-week, when it comes to sunshine--that's the forecast from KPLU weather expert Cliff Mass, of the University of Washington.

But, it won't exactly be warm and sunny.

Instead, a weak weather system will send most of its moisture toward Portland and British Columbia, leaving some clouds and potentially a few brief rain showers over western Washington.

And, whatever you do, don't ask Mass if any strange weather of the past month is due to global warming. That really bugs him:

"I think there's been a lot of hype and exaggeration about recent weather events. People see an extreme event and try to suggest that that's due to global warming ... and I think a lot of these connections are very weak."

For example, the recent heat wave on the east coast, he says, has been analyzed by the best scientists at NOAA, who also analyzed the Russian heat wave of last year. They concluded those were due to "natural variability."

"One event, an individual event, doesn't really tell you anything. But if you look over a period of decades, and you see these extreme events happening more and more frequently ... then that's a signature that we are really doing something," he says.

That means, we'll only know long after the fact, when we look back in time, that any particular series of storms, tornados, or heat waves was related to climate change.

As Mass concludes on his blog (with his own bold letters):

I believe the science is fairly clear...the impacts of global warming due to human-enhanced greenhouse gases will be be very significant, that the effects will increase gradually at first, but then accelerate later in the century.  There will be substantial impacts on extremes, but the magnitudes and spatial distributions will be complex, and we don't necessarily have a good handle on it at present.

(You can find a lively debate in the comments there, too)

Get more details in the weekly interview.

Do you have a weather question? Cliff Mass and Keith Seinfeld occasionally answer reader questions on the air. Share yours here.

The weekly KPLU feature "Weather with Cliff Mass" airs every Friday at 9 a.m. immediately following BirdNote, and repeats twice on Friday afternoons during All Things Considered. The feature is hosted by KPLU’s Science and Health reporter Keith Seinfeld. Cliff Mass is a University of Washington Professor of Atmospheric Sciences, a renowned Seattle weather prognosticator, and a popular weather blogger. You can also subscribe to a podcast of “Weather with Cliff Mass” shows.